Figure 6.

Left: RHEED patterns observed during Ge growth at 600°C on stripe-patterned Si substrates
with “V” geometry (see Fig. 2b) at Ge thicknesses of 0, 2, 4.2, 4.8, and 6 ML from (a) to (f), respectively. The onset of dome island formation at ~5ML coverage is indicated
by the appearance of 3D diffraction spots in the RHEED patterns (see dashed circle). Right: Intensity evolution as a function of coverage of the specular spot, 3D ripple, and
3D island spot (purple, blue, and red line, respectively) indicated by the dashed square and circle in (f). As indicated by the vertical dashed lines, the onset of ripple formation occurs at a critical coverage of 4.6 ML, whereas dome
nucleation sets in at critical coverage of 5 ML